package com.atguigu.gulimall.product.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.*;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {


    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        //1.查出所有分类
        List<CategoryEntity> categoryEntityList = baseMapper.selectList(null);
        //2.组装成父子的树形结构
        List<CategoryEntity> levelMenus = categoryEntityList.stream()
                .filter(categoryEntity -> categoryEntity.getParentCid() == 0)
                .map(menu -> {
                    menu.setChildren(getChildren(menu, categoryEntityList));
                    return menu;
                })
                // .sorted((menu1, menu2) -> menu1.getSort() - menu2.getSort()) //和下面等价
                .sorted(Comparator.comparingInt(CategoryEntity::getSort))
                .collect(Collectors.toList());

        return levelMenus;
    }

    /**
     * 通过当前menu 从 menus 中查找子分类
     *
     * @param root menu
     * @param all  menus
     * @return 子分类
     */
    private List<CategoryEntity> getChildren(CategoryEntity root, List<CategoryEntity> all) {
        return all.stream()
                .filter(menu -> Objects.equals(menu.getParentCid(), root.getCatId()))
                .map(menu -> {
                    menu.setChildren(getChildren(menu, all));
                    return menu;
                })
                .sorted(Comparator.comparingInt(CategoryEntity::getSort))
                .collect(Collectors.toList());
    }

}